Centrifuge



March 30, 1965 H. A. DINTER, JR

GENTRIFUGE Filed June 25. 1962 2 Sheets-Sheet 1 FIG 25 26 FLUID I L74llllllllllllllzl 'Tflllllllllllllllllllllllllllllllll I INVENTOR. HENRYA. DINTER,JR. Bi a ATTORNEY March 30, 1965 H. A. nlN'rER, JR 3,175,762

CENTRIFUGE Filed June 25. 1962 2 Sheets-Sheet 2 FIG. 3 69 (64 (-66TEMPERATURE CONTROLLER 67 65 HEAT 63 ExcHANGERN-W T0 *S :3) W( ExcHANGER72 78 l.

L! HEAT ExcHANsER T 25 9o 89 v`'VVE' 9| I---ww HEAT /87 es 93 ExcHANGER92 HEAT,i

' INVENTOR. ExcHANGER HENRY A. D|NTER,JR.

ATTORNEY 3,175,762 CENTRIFUGE Henry A. Dinter, Jr., Minneapolis, Minn.,assigner to Honeywell Inc., a corporation of Delaware Filed June 25,1962, Ser. No. 204,776 3 Claims. (Cl. 233-11) This invention pertains tocontrol apparatus and more particularly to that type of controlapparatus generally referred to as a centrifuge.

The applicants unique centrifuge has special application to the field ofbiological research, valthough it is not limited to this type ofapplication. The applicants unique vcentrifuge provides iiuid bearingsupport of the rotatable element and precise temperature control of thespecimen cavities therein. The applicant has provided a temperaturecontrol means in which the average temperature of the specimen cavity iscontrolled to a precise temperature and the temperature gradient acrossthe specimen cavity is substantially eliminated.

It is therefore an object of this invention to provide an improvedcontrol apparatus.

This and other objects of the invention will become apparent Ifrom astudy of the accompanying specification and claims in conjunction withthe drawings in which:

FIGURE 1 is a schematic elevation view partially in cross section of theapplicants centrifuge;

FIGURE 2 is a schematic end View of the rotatable element of theapplicants centrifuge;

FIGURE 3 is a schematic diagram of the average temperature controlsystem of the applicants centrifuge; and

FIGURE 4 is a schematic diagram of the temperature gradient controlsystem of the applicants centrifuge.

Referring now to FIGURE 1, reference numeral 1t? generally depicts theapplicants unique centrifuge. A housing means is identified by referencenumeral 11. Housing means 11 consists of a base portion 12 and atemperature lag portion 13. Base portion 12 may be fabricated ofstabilized cast steel or other suitable material. Temperature lagportion 13 is fabricated out of copper in the ernbodiment illustratedbecause of its superior heat transfer characteristics. Temperature lagportion 13 contains an annular fluid cavity 14 therein. An inputconnector 15 connects cavity 14 to a heat exchange iiuid source (notshown). An output connector 16 connects cavity 14 to a heat exchangerand to a fluid pump (not shown).

A rotatable element or shaft means 17 is mounted upon housing means 11so as to rotate about an axis 18. Rotatable element 17 has an enlargedradius section 19 thereon. Enlarged radius section 19 contains fourspecimen cavities therein symmetrically located about axis 18. Thecavities are identified by reference numerals Ztl, 21, 22 and 23 and areillustrated in FlGURE 2. lt should be pointed out that the applicantdoes not wish to be limited to any specific number of cavities; a singlecavity or a plurality of cavities may be utilized. 1t should also bepointed out that although rotatable means 17 is fabricated from a singlebar of stainless steel, in the embodiment illustrated, it is possible toconstruct the rotatable means 17 out of two or more component parts. Acylindrical central chamber 24 is located within rotatable element 17concentric with axis 18 and having an axial extent substantially equalto the axial extent of rotatable element 17. An instrumentation spindleS is attached to the end of 4rotatable element 17 contiguous enlargedradius section 3,175,762 Patented Mar. 30, 1965 19. Spindle 55 providesa mounting means for certain elements of the temperature control meansto be explained hereinafter.

The rotatable element 17 is mounted upon housing 11 by means of -afluid, gas or hydrostatic bearing means 25. A fluid 26 which supportsthe rotatable element 17 is introduced from a suitable source (notshown) into 'an annular distribution manifold 27. Fluid 26 ows frommanifold 27 through a plurality of radial orifices to a plurality ofpressure pads 28. Fluid 26 flows into a radial bearing clearance 29 fromthe pressure pads so as to provide radial support of the rotatableelement 17. Thrust support is provided for rotatable element 17 as iiuid26 leaves clearance 2.9 past an end restrictor 3G land an end restrictor31 upon rotatable element 17. Fluid 26 flows from clearance 29 through aplurality of radial orifices 35, 36 and 37 into central chamber 24 ofrotatable element 17. Fluid 26 flows through central chamber 24 fromright to left as viewed in FIGURE l, and exhausts from chamber 24through a plurality of axial orifices 33 and 39. A charnber 46 isprovided between the end of rotatable element 17 and housing means 11.Fluid 26 flows from chamber 24 into chamber 40 through orifices 33 and39. A portion of fluid 26 Hows from clearance 29 past end restriction311 into chamber 40. Fluid 26 exhausts from chamber 4l) through anoutlet connector 41.

A drive motor 45 is provided to rotate the rotatable element 17. Drivemotor 45 may be of any suitable hysteresis synchronous motor typedesigned to operate at a particular angular velocity. It is possible toutilize a drive motor designed to operate at a plurality of definiteangular velocities. Drive motor 45 is attached to housing means 11 bymeans of bolts 46 and is coupled to rotatable element 12 by means of -aflexible coupling 47.

Means are provided, as at 53, to utilize an optical pickof arrangement.Although the optical pickotf means forms no part of the presentinvention it should be noted that the overall design of the applicantsunique centrifuge provides an optical path which is unimpeded by anyparts of the centrifuge.

Referring now to FlGURE 2 a thermocouple 61 is imbedded in enlargedradius section 19 of rotatable element 17 adjacent to cavity 29.Thermocouple 61 monitors the average temperature of cavity 21B in oneembodiment of the applicants invention. Leads from thermocouple 61 (notshown) are positioned within a lead path 62 and connect thermocouple 61in opposed series relationship with a thermocouple 63 mounted uponrotatable element 17 contiguous with axis 18. Therrnocuple 61 andthermocouple 63 form a differential thermocouple. 'Ihermccouple 63 isrigidly attached to and rotates with rotatable element 17. Thermocouple63 is positioned within a chamber 64 within temperature lag portion 13of housing means 11. Chamber 64 is heated or cooled by a heat exchangefiud flowing through a fluid cavity 69 within temperature lag portion 13of housing 11 and contiguous chamber 64. The heat exchange fluid enterscavity 69 by means of a connector 73 and exhausts from cavity 69 bymeans of a connector 74. A thermocouple 65 is mounted upon temperaturelag portion 13 of housing 11 and within chamber 64 adjacent tothermocouple 63. Thus thermocouple 63 and thermocouple 65 sense the sametemperature.

A temperature controller 66 utilizes the output voltage from thedifferential thermocouples 61, 63, to control the temperature of a heatexchange fluid which controls the temperature of chamber 64. Thetemperature of chamber 641s set at a desired temperature. Thistemperature is monitored by thermocouple 65 and controlled by thetemperature controller 66 and a heat exchange fluid. A difference intemperature between thermocouple 63 (which is at the same temperature asthermocouple 66) and thermocouple 61 results in an output voltage whichis indicative of the temperature differential between cavity 20 andchamber 6d. The output voltage yof differential thermocouple 61, 63 isutilized to control the temperature of a heat exchange fluid which isintroduced into cavity 14 within housing 11 so as to maintain theaverage temperature of cavity 20 at the particular value desired. By socontrolling the average temperature of cavity 20, the averagetemperature of cavities 21, 22 and 23 is also controlled. Because of thesymmetrical construction of centrifuge 10, each cavity will have thesame average temperature as cavity 2t).

It is also possible to utilize a separate thermocouple for each cavity.In this embodiment, the thermocouples would be connected in a seriesrelationship. This results in an output signal of a higher magnitudethan is obtained when utilizing a single thermocouple. The thermocouplesof controlling the average temperature of cavities 21, 22 and 23 will beidentical to thermocouple 61. Consequently no further discussion of thisalternate embodiment is deemed necessary.

A thermocouple 70 is imbedded near the periphery of enlarged radiussection 19 of rotatable element 17 and adjacent to cavity 2t). Athermocouple 71 is imbedded within enlarged radius section 19 ofrotatable element 17 adjacent to cavity 20 but displaced radially inwardfrom thermocouple 70. As illustrated in FIGURE 2, thermocouples 70 and71 are disposed on opposite sides of cavity 2t). Thermocouple 71) andthermocouple 71 are connected in opposed series relationship so as toform a differential thermocouple. The leads (not shown) of thermocouple70 and thermocouple 71 are positioned within a lead path 72 to conductthe output voltage to spindle 55. The output voltage from differentialthermocouple '79, 71 is indicative of the temperature difference ortemperature gradient across cavity 2G. The output voltage ofdifferential thermocouple 70, 71 is utilized to conduct the outputvoltage to spindle 55. The output voltage from differential thermocouple70, 71 is utilized to control the temperature of fluid 26 of uid bearingmeans 25. A change in temperature of fluid 26 results in a change intemperature of that portion of rotatable element 17 in contact withfluid 26. This change in temperature is conducted radially outwardthrough enlarged radius section 19 of rotatable element 17 so as tosubstantially eliminate any temperature gradient existing across cavity20. By so controlling the temperature gradient across cavity 20, thetemperature gradient across cavities 21, 2.2 and 23 is also controlled.Because of the symmetrical construction of centrifuge 1G, each cavitywill be controlled the same as cavity 20.

It is also possible to utilize a separate set of thermocouples for eachcavity. In this embodiment, each set of thermocouples would be connectedin a series relationship. This results in an output signal of a highermagnitude than is obtained when utilizing a single set of thermocouples.The -thermocouples for controlling the temperature gradient acrosscavities 21, 22 and 23 will be identical to the thermocouples 61, 63.Consequently, no further discussion of this alternate embodiment isdeemed necessary,

A plurality of slip rings 56 are provided between spindle 55 and housing11 so that the output voltage of differential thermocouple 61, 63 anddifferential thermocouple 70, 71 may be conducted from rotatable element17 to the stationary housing 11.

The operation of the temperature control means of the applicantscentrifuge can best be explained with reference to FIGURES 3 and 4.Fl'GURE 3 is a schematic diagram of the means for controlling theaverage temperature of cavities 2t), Z1, Z2 and 23. The temperature inchamber 64 is monitored by thermocouple 65. The output voltage ofthermocouple 65 is connected to a temperature controller 66 which inturn functions to control the energization of a heater 67 of a heatexchanger 68, heat exchange iluid is pumped by means of `a pump "70through a valve 71 into heat exchanger 63 When a sufficient amount ofheat has been added to the heat exchange tiuid it is pumped to a cavitysurrounding chamber 64 to control the temperature thereof. The heatexchange tluid leaves chamber 64 and is conducted through arefrigeration unit or heat exchanger 72. The heat exchange fluid isconnected from iiuid heat exchanger 72 to the pump means 76 to completea first liuid loop.

As pointed out previously, the average temperature of cavity Zt) issensed by thermocouple 61 which is ditferentially connected tothermocouple 63. The average temperature desired for cavity 26 is thetemperature at which chamber 64 is maintained. Thermocouple 65 andthermocouple 63 are positioned adjacent to one another within chamber 64and sense the same temperature. Consequently, should thermocouple 61sense a different temperature than Vthermocouple 63 annoutput voltage isgenerated which is indicative of the difference in temperature betweenthermocouple 61 and .thermocouple 63. Stated otherwise, the outputvoltage isindic-I ative of the temperature differential between `cavityand chamber 64. The output voltage from diiferential thermocouple 61, 63is conducted through slip ring means 56 to an amplifier means '75. Theoutput of amplifier means 75 is utilized to control a heater element 76within a heat exchanger 77. l A feedbachlsensor 73 is also positionedwithin heat exchanger 77. The output of feedback sensor 73 is connectedto Ian amplitier 79. The output of amplifier 79 is connected to theinput of amplifier 75 so as to complete the servo loop.

Heat exchange fluid is also directed from pump '745 through a valve 79and into heat exchanger 77 Where a certain amount of heat is added tothe fluid by means of energization of heater element '76. Heater -7-6 iscontrolled by the output voltage of differential thermocouple means 61,63. Heat exchange uid flows from heat ex changer 77 to annular chamber14 in temperature lag' portion 13 of housing 11. The fluid flows fromannular chamber 14 back to heat exchanger 72 where it is cooled and thenback to pump 7) to complete a second tiuid loop.

In summary, chamber 64 is set at a desired temperature and maintained atthis temperature by means of heat exchange fluid. A difference betweenthe average teniperature of cavity 20 and the temperature of chamber 64results in an output voltage from differential thermocouple 61, 63 whichis utilized to control the temperature of a heat exchange fluid so as todrive the average temperature of cavity 20 to the desired temperature(the temperature of chamber 64).

The means controlling the temperature gradient of cavities 2li-23 isillustrated in FIGURE 4. As hereinbefore discussed, thermocouple 7@ andthermocouple 71 are connected to form a differential thermocouple. Theoutput voltage generated by differential thermocouple 76, 71 isindicative of a temperature differential therebetween. The output signalof differential thermocouple '70, 71 is conducted through slip ringmeans 56 to the input of an amplifier means 85. The output of amplifiermeans S5 controls the energization of a heater means 86 of a heaterexchanger 37. A feedback sensor 88 is also contained within heatexchanger 87. The output of feedback sensor 88 is connected to the inputof an amplifier means 89. The output of amplifier means 89 is connectedback to the input of amplifier means S5 so as to complete the servoloop.

A supply 90 of fluid 26, for example, hydrogen, for

fiuid bearing means 25 is provided at the required pressure. Fluid 26 issupplied to a heat exchanger 91 where it is cooled somewhat below thedesired temperature. The fluid 26 is cooled by means of a heat exchangeror Irefrigeration unit 92 which circulates a coolant through heatexchanger 91 by means of a pump 93. A temperature control thermostat andrelated items for heat exchanger 91 are not illustrated in FIGURE 4. Thefiuid 26 is conducted from heat exchanger 91 in a cool state and isconducted to a heat exchanger S7. if a temperature differential existsbetween differential thermocouple 70, '71 the output voltage therefromwill be utilized to energize heater S6 so as to heat fluid 26 to thecorrect temperature. Fluid 26 is conducted from heat exchanger 87 tobearing means 25, circulates therethrough, and is expelled out of outletconnector 41. It should be noted that the iiuid 26 is cooledsufficiently to counteract the heat added to rotatable element 17 due tothe viscous shear of the fluid 26.

Thus the applicant has provided aunique centrifuge in which therotatable element is supported by means of a fiuid bearing in which heprovides temperature control means to control the average temperature ofthe specimen cavity and the temperature gradient across the specimencavity. The temperature gradient is substantially eliminated byutilizing the fluid of the fluid bearing means.

While I have shown and described a specific embodiment of thisinvention, further modifications and improvements will occur to thoseskilled in the art. I desire it to be understood, therefore, that thisinvention is not limited to the particular form shown and I intend inthe appended claims to cover all modifications which do not depart fromthe spirit and scope of this invention.

I claim:

l. An apparatus of the class described: housing means; a shaft elementhaving an enlarged radius section thereon, said shaft element beingpositioned within said housing means; hydrostatic bearing meansrotatably supporting said shaft element for rotation about an axis, saidhydrostatic bearing means utilizing a first fluid; means for rotatingsaid shaft about said axis; said housing means having an annular cavitytherein surrounding said enlarged radius section of said shaft element;said housing means having a chamber therein contiguous one end of saidshaft element; said enlarged radius section having a specimen cavitytherein; means for controlilng the average temperature of said specimencavity including a first thermocouple positioned contiguous saidspecimen cavity and a second thermocouple positioned upon said shaft andWithin said chamber, said first thermocouple being connected to saidsecond thermocouple so as to provide a first output signal indicative`of the temperature differential between said specimen cavity and saidchamber; said means for controlling the average temperature furtherincluding means responsive to said first output signal for controllingthe temperature of a second fluid adapted to flow through said annularcavity Within said housing means, a change in temperature of said secondfluid being effective to change the average temperature of said specimencavity; means for controlling the temperature gradient across saidspecimen cavity including a third thermocouple and a fourth thermocouplepositioned contiguous to and on opposite sides of said specimen cavity,said third thermocouple being connected to said fourth thermocouple soas to provide a second output signal indicative of the temperaturegradient across said specimen cavity; and said means for controlling thetemperature gradient further including means responsive to said secondoutput signal for controlling the temperature of said first fluid tosaid hydrostatic bearing means, a change in the temperature of saidfirst fiuid being effective to reduce the temperature gradient acrosssaid specimen cavity.

2. An apparatus of the class described: housing means; a shaft elementhaving a first section thereon, said shaft element being positionedwithin said housing means; hydrostatic bearing means rotatablysupporting said shaft element for rotation about an axis, saidhydrostatic bearing means utilizing a first fluid; means for rotatingsaid shaft about said axis; said housing means having an annular cavitytherein surrounding said first section of said shaft element; saidhousing means having a chamber therein; said first section having aspecimen cavity therein; means for controlling the average temperatureof said specimen cavity including a first sensor means positionedcontiguous said specimen cavity and a second sensor means positionedupon said shaft and within said chamber, said first sensor means beingconnected to said second sensor means so as to provide a first outputsignal indicative of the temperature differential between said specimencavity and said chamber; said means for controlling the averagetemperature further including means responsive to said first outputsignal for controlling the temperature of a second fluid adapted to flowthrough said anunular cavity within said housing means, the temperatureof said second fluid being effective to control the average temperatureof said specimen cavity; means for controlling the temperature gradientacross said specimen cavity including a third sensor means and a fourthsensor means positioned contiguous to and on opposite sides of saidspecimen cavity, said third sensor means being connected to said fourthsensor means so as to provide a second output signal indicative of thetemperature gradient across said specimen cavity; and said means forcontrolling the temperature gradient further including means responsiveto said second output signal for controlling the temperature of saidfirst fiuid to said hydrostatic bearing means; the temperature of saidfirst fluid being effective to control the temperature gradient acrosssaid specimen cavity.

3. An apparatus of the class described: housing means; a shaft elementhaving a first section thereon, said shaft element being positionedwithin said housing means; hydrostatic bearing means supporting saidshaft element for rotation about an axis, said hydrostatic bearing meansutilizing a first fluid; means for rotating said shaft about said axis;said housing means having an annular cavity therein surrounding saidfirst section of said shaft element; said housing means having a chambertherein; said first section having a specimen cavity therein; means forcontrolling the average temperature of said specimen cavity including afirst sensor means positioned contiguous said specimen cavity and asecond sensor means positioned upon said shaft and within said chamber,said first sensor means being connected to said second sensor means soas to provide a first output signal indicative of the temperaturedifferential between said specimen cavity and said chamber; said meansfor controlling the average ternperature further including meansresponsive to said first output signal for controlling the temperatureof a second fiuid adapted to flow through said annular cavity withinsaid housing means so as to control the average temperature of saidspecimen cavity; means for controlling the temperature gradient acrosssaid specimen cavity including a third sensor means and a fourth sensormeans positioned contiguous to and on opposite sides of said specimencavity, said third sensor means being connected to said fourth sensor-means so as to provide a second output signal indicative of thetemperature gradient across said specimen cavity; and said means forcontrolling the temperature gradient further including means responsiveto said second output signal for controlling the temperature of saidfirst fluid to said hydrostatic bearing so as to reduce the temperaturegradient across said specimen cavity.

References Cited by the Examiner UNITED STATES PATENTS (References onfollowing page) UNITED STATES PATENTS Ayres 233-23 McBain 233-23 XRapsarda 165-39 X Peters 165-39 Hosack 165-89 X Beams 233-24 Melton233-11 X Cizusky 233-23 GEORGE D. MITCHELL, Primary Examiner.

Pickels @t al- 233-26 10 ROBERT F. BURNETT,Examiner.

1. AN APPARATUS OF THE CLASS DESCRIBED: HOUSING MEANS; A SHAFT ELEMENTHAVING AN ENLARGED RADIUS SECTION THEREON, SAID SHAFT ELEMENT BEINGPOSITIONED WITHIN SAID HOUSING MEANS; HYDROSTATIC BEARING MEANSROTATABLY SUPPORTING SAID SHAFT ELEMENT FOR ROTATION ABOUT AN AXIS, SAIDHYDROSTATIC BEARING MEANS UTILIZING A FIRST FLUID; MEANS FOR ROTATINGSAID SHAFT ABOUT SAID AXIS; SAID HOUSING MEANS HAVING AN ANNUALR CAVITYTHEREIN SURROUNDING SAID ENLARGED RADIUS SECTION OF SAID SHAFT ELEMENT;SAID HOUSING MEANS HAVING A CHAMBER THEREIN CONTIGUOUS ONE END OF SAIDSHAFT ELEMENT; SAID ENLARGED RADIUS SECTION HAVING A SPECIMEN CAVITYTHEREIN; MEANS FOR CONTROLLING THE AVERAGE TEMPERATURE OF SAID SPECIMENCAVITY INCLUDING A FIRST THERMOCOUPLE POSITIONED CONTIGUOUS SAIDSPECIMEN CAVITY AND A SECOND THERMOCOUPLE POSITIONED UPON SAID SHAFT ANDWITHIN SAID CHAMBER, SAID FIRST THERMOCOUPLE BEING CONNECTED TO SAIDSECOND THERMOCOUPLE SO AS TO PROVIDE A FIRST OUTPUT SIGNAL INDICATIVE OFTHE TEMPERATURE DIFFERENTIAL BETWEEN SAID SPECIMEN CAVITY AND SAIDCHAMBER; SAID MEANS FOR CONTROLLING THE AVERAGE TEMPERATURE FURTHERINCLUDING MEANS RESPONSIVE TO SAID FIRST OUTPUT SIGNAL FOR CONTROLLINGTHE TEMPERATURE OF A SECOND FLUID ADAPTED TO FLOW THROUGH SAID ANNULARCAVITY WITHIN SAID HOUSING MEANS, A CHANGE IN TEMPERATURE OF SAID SECONDFLUID BEING EFFECTIVE TO CHANGE THE AVERAGE TEMPERATURE OF SAID SPECIMENCAVITY; MEANS FOR CONTROLLING THE TEMPERATURE GRADIENT ACROSS SAIDSPECIMEN CAVITY INCLUDING A THIRD THERMOCOUPLE AND A FOURTH THERMOCOUPLEPOSITIONED CONTIGUOUS TO AND ON OPPOSITE SIDES OF SAID SPECIMEN CAVITY;SAID THIRD THERMOCOUPLE BEING CONNECTED TO SAID FOURTH THERMOCOUPLE SOAS TO PROVIDE A SECOND OUTPUT SIGNAL INDICATIVE OF THE TEMPERATUREGRADIENT ACROSS SAID SPECIMEN CAVITY; AND SAID MEANS FOR CONTROLLING THETEMPERATURE GRADIENT FURTHER INCLUDING MEANS RESPONSIVE TO SAID SECONDOUTPUT SIGNAL FOR CONTROLLING THE TEMPERATURE OF SAID FIRST FLUID TOSAID HYDROSTATIC BEARING MEANS, A CHANGE IN THE TEMPERATURE OF SAIDFIRST FLUID BEING EFFECTIVE TO REDUCE THE TEMPERATURE GRADIENT ACROSSSAID SPECIMEN CAVITY.